(a) Field of the Invention
The present invention relates to electric connectors, and particularly to a connecting method of pins and tin balls of an electric connector, wherein a plurality of pins of the electric connector resist against tin balls so as to position the pins; the lower ends of the pins store elastic energy due to the resisting contact. Thereby, the lower end of the pin is well conductive to a PC board and the yield.
(b) Description of the Prior Art
Referring to FIGS. 16 to 18, the prior art connecting way of pins of electric connector and tin balls are illustrated. A layer of weld-assisting agent is coated at a lower end 101 of the pin 10 of an electric connector so as to combine the tin ball 30 to the lower end 101 of the pin 10. Then, the PC board 40 is welded with the electric connector by blowing heated air and thus the tin ball 30 is melted and welded to a lower end of the pin 101 and the joint 401 of the PC board. With reference to FIG. 18, the dashed line shows a preferred connection. Substantially, the prior art welding operation will generate a siphon effect due to the blowing operation. Thereby, after the tin ball 30 is melted, the tin liquid will be absorbed upwards so that most of the tin liquid is condensed to the lower end 101 of the pin. Only a small amount tin liquid is adhered to the joint 401 of the PC board. Thus the connection is not preferred and dull welding occurs (see the solid line in FIG. 18, where the melted tin ball is not in contact condition). Thus, the lower end 101 of the pin is not preferably conductive to the joint 401 of the PC board. As a result, the function of the electric connector is not preferred and the yield ratio is low.